


Baby Troubles

by Rust72



Category: Undertale (Video Game)
Genre: Brotherly Love, Experiment gone wrong, Gaster mentioned - Freeform, Grillby really likes babies, Mother Brother, baby blaster au, oh spagetti why did i write this, sans is such a cute baby
Language: English
Status: Completed
Published: 2016-02-11
Updated: 2017-02-10
Packaged: 2018-05-19 18:22:45
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 16
Words: 7,435
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5976691
Author URL: https://archiveofourown.org/users/Rust72/pseuds/Rust72
Summary: <blockquote class="userstuff">
              <p>When sans agrees to help Alphys test her new machine, he accidently get turned into a tiny, weak baby. Papyrus is stuck taking care of him till Alphys fixs the problem. May the cuteness begin</p>
            </blockquote>





	1. Chapter 1

Chapter 1: the experiment

As much as sans loved to sit around, he also found great joy in science. It was a normal day when he got a call from alphys. Alphys knew sans was a science geek, and was hoping that he would help test a new experiment she was working on. “U-um, w-would you like to come over, a-and help me test my new machine?” she asked. Sans was quiet for a moment, then laughed. “That would be sans-sational.” He snorted. “uhg.” Alphys groaned as she hung up the phone. It wasn’t no more than an hour when sans showed up at the scientist’s lab. “Knock, knock.” Sans called as he rasped his bony knuckles on the steel door. Alphys opened it, waving for him to come in. “so this is what you’ve been up to.” Sans said, examining the ray gun that sat in the middle of the room. “Well, y-yes. It’s supposed to weaken the barrier, but I don’t know if it will work.” She said, her voice quiet. “Well, let’s try it.” Sans said gleefully. He always loved things like this; ray guns and such. Alphys charged the power, a green aura forming at the end of the gun. But then there was a crash and the beam lost power. “Dang it! It got jammed.” Alphys cursed. “Don’t worry, I’ll get it.” Sans said, stepping in front of the gun. “No, sans don’t stand there it’s,” she was cut off as the gun suddenly shot a beam, hitting sans in the face. There was a flash of light and smoke as the gun cooled down. Rubbing her eyes, alphys glanced around trying to find sans. “Sans?” she called. Stepping closer to where he once stood, alphys was frozen from the sight in front of her. Sans was gone, only his clothes remaining in a heap on the floor. “no.” alphys coughed, falling to her knees next to the clothing heap. “What have I done?” she sobbed. Then she heard it, a small whimper. She glanced at the pile to see something moving underneath. Carefully, she pulled back sans coat, revealing a small baby bones. He wiggled and whimpered in attempt to find warmth. He opened his tiny eyes and glanced up at Alphys, a blue tint on his cheeks. Tears welled up in his eyes as he let out a small cry of fear. “No, no, please don’t cry.” Aphys reassured. She wrapped him in the oversized coat, cradling him in her arms. He still cried, but quieter. “Oh god. What do I do?” She gasped as she ran around the room. “I should call papyrus. He’d know what to do.” She finally said.


	2. Mamma Brother

**Notes for the Chapter:**

> I can't spell. sorry

Training with Undyne was always fun, even if it was just making spaghetti. “Come on Papyrus! Put you back into it!” Undyne yelled as Papyrus punched some tomatoes. “All right! This will defiantly make a great sauce that might rival me, the great Papyrus.” he called, picking up his speed. RING, RING. 

The sound of Papyrus’s phone made him stop and glance back at the table. “Hm, who could be calling?” he said. He shrugged it off, knowing that it was probably nothing important. But after a few more minutes, it rang again. This time, Papyrus felt inclined to answer it. “Can we take a break for a moment, Undyne?” Papyrus asked, wiping off his gloves. “You better make it quick or I’ll double the recipe.” Undyne laughed. Taking it as a warning, papyrus quickly answered the phone. 

“Hello, this is the Great Papyrus.” he said. “P-papyrus, I’m sorry.” Alphys whimpered. “A-alphys? Whatever could be wrong?” Papyrus stuttered. “It’s all my fault, I wasn’t being careful. S-sans, he’s, he’s.” alphys didn’t even get to finish her sentence as Papyrus hung up. Rushing out of Undyne’s, papyrus ran to the lab. He banged on the door franticly. “Alphys, please open!” he yelled. 

The door opened and Papyrus rushed inside. Alphys stood clutching the hoodie to her chest, her face full of regret. “s-sans.” Papyrus breathed, looking down at the jacket. He eyes began to fill with tears as he fell to his knees. “No, no. he can’t be gone.” Papyrus sobbed. Suddenly he heard a small cry from the hoodie, leaning in closer to get a better look. 

There he saw it, his brother, in baby form. Baby sans looked up at his brother, his lip quivering. Sans reached out for Pap, letting out another cry. He remembered Pap. Papyrus took the bundle carefully, smoothing the small tears away from sans face. Tiny fingers clamped down on Papyrus’s phalange, taking it to his mouth to suckle. A small orange blush formed on Papyrus’s cheeks as he glanced up at alphys. “What happened?” he demanded.   
Alphys explained the entire situation, at some point sans had fallen asleep. “It’s best you t-take him home. I-I’ll find a way to turn him back.” Alphys explained. Papyrus nodded his head, then left the lab.


	3. Warmth

**Notes for the Chapter:**

> I'm sorry if some of this is sloppy. I'm not the best writer so bare with me

Making it out of Hotland and waterfall, papyrus entered the snowy town of Snowdin. He glanced down every once and a while to check on his brother to see nothing had really changed. But as they entered Snowdin, Papyrus noticed a change in his tiny brother. Sans face was full of discomfort and he shook from the cold.  
He had nothing more than a coat covering him and being a skeleton, Papyrus couldn’t produce any warmth. He began to get nervous, picking up his pace. It was now late and pretty much all of the town’s inhabitants had gone to bed. But there was one person Papyrus knew would still be awake and he was just approaching his establishment. Grillby’s was always a warm place, and it seemed sans found that appealing. Grillby, the owner of the small bar, was just locking up his door when papyrus ran up to him. “Grillby, you’ve got to help me.” Papyrus cried. “What’s wrong? Wait, is that sans coat?” Grillby replied.  
Slowly, papyrus handed Grillby the small bundle, taking it with soft hands. He stared down silently, examining his best customer. “What happened?” he asked, his voice soft. “It’s a long story, but I need your help. I’m a skeleton, I don’t produce heat, and sans is cold!” papyrus said. Grillby looked at him, then back at sans. Sans was now awake, his small bones rattling from the cold. But he seemed calm, like he knew that he was safe with Grillby.   
Taking a deep breath, Grillby hugged sans against his chest. Being a baby, sans nestled perfectly against Grillby’s chest, cooing as the heat warmed him. “This should help.” Grillby said. “Thank you Grillby. You’re a life saver.” Papyrus beamed. Grillby could feel a cool blush on his cheeks, looking away for a moment. He never really wanted anyone to know, but he absolutely loved babies. “Maybe you should come back to my place. I might have some old baby clothes from when my niece stayed here.” He said, pointing in the direction of his home. Papyrus nodded his head, and followed the fire elemental thought the soft snow.  
Grillby’s house wasn’t very large, but big enough for a one child family. Handing sans back to Papyrus, he motion for them to sit on the couch. “Wait here, I’ll go see what I can find.” Grillby said as he climbed the stairs. Papyrus nodded, cuddling sans tighter. San cooed in response, reaching up his small hand to touch Papyrus’s malleable.  
“I never realized how cute you were as a baby.” Papyrus whispered. Sans looked at him with large pupils. He reached out again, his hand trying to grasp something. “Pa, pa.” sans cooed. “Are you trying to say my name?” papyrus asked in excitement. “pa.” sans said louder. It seemed that was as much as he was going to get out of him. “Having fun I see.” Grillby said as he descended the stairs. An orange glow was painted across papyrus’s cheeks. “w-well, he is my brother.” Papyrus stuttered.   
Grillby hummed in agreence. He placed down on the floor a pile of clothes and blankets. Taking a blanket from the pile, he spread it out on the floor. “Here, let me get him dressed.” Grillby said. He took sans from papyrus’s arms and laid him on the floor. Now that he was unswaddled, they could examine his small frame. No broken bones and dislocations. His head had small soft spots, and his soul was bright in his chest. Sans wiggled in the new found cold, tears welling up in his eyes.  
“Don’t worry, sans. Once you’re dressed you won’t be so cold.” Grillby hushed. Sans stopped wiggling as Grillby dressed him in a plain gray onesie. Buttoning the last button, Grillby sat back and admired his work. Sans was swaddled warmly in his new clothes, a smile running across his face. “I believe this will do.” Grillby said as he turned to Papyrus. “You’re so god at this Grillby!” Papyrus chirped. “grrr.” Came a small muffled voice. The two looked down to see sans reaching up to Grillby. “grrrrr.” He said again. “Gasp, he’s trying to say your name.” papyrus vibrated. Grillby picked sans up, holding him at eye level. “You are going to be a lot of trouble.” Grillby said. Sans only laughed at it.


	4. A Glitch

**Summary for the Chapter:**

> It finally calmed down in the Skeleton home, but that soon ends.

**Notes for the Chapter:**

> Short chapter but whatever. PLEASE IF YOU ARE READING THIS GO CHECK OUT MY STORY "THE HOSPITAL"! Trust me, it's really good.

It had been a week since sans’s transformation, and Grillby was getting tired. He was now living with the two brothers, helping out with taking care of sans. But sans wasn’t a sound sleeper. He’d wake up and scream at least three times a night. Grillby would do what he could, but it was Papyrus who always came to save the day. Maybe it was just a brother thing. As soon as sans was in Papyrus’s grasp, he went immediately silent. After three troublesome nights, they decided to move sans into Papyrus’s room. After that, sans only woke up one time each night. 

With that great accomplishments came even better ones. Sans began to crawl, well, more of a wiggle. He also began to make sounds that seemed more like names. “Papy, Gib!” he would yell. Though it wasn’t close, it was good enough. But they were worried. Alphys was trying her best to find a cure, but it wasn’t getting anywhere. Papyrus was getting nervous. He was the younger brother, and now sans was smaller than him. And if they couldn’t turn him back, how would that affect sans. “Papy!” sans called from the other room. Papyrus walked out, spaghetti in one hand and a bottle in the other. Sans was on the floor, a crayon in his mouth. He was just learning to sit on his own, and when he saw Papyrus, ended up on his face. “Sans, don’t be so reckless.” Papyrus sighed. “Papy!” sans yelled again. His smile was wide, blue blush on his small cheek bones. Papyrus could feel his soul become warmer. His brother really was cute. 

“Here, it’s time to eat.” Papyrus said as he sat sans up. Sans took the bottle happily, but stopped when he saw the spaghetti. He seemed entranced by the plate, which gave Papyrus an idea. “You want to try it?” he asked. Sans looked up and smiled. Suddenly, he jumped forward and landed with his hands in the spaghetti. Then he proceeded to stuff it in his mouth, dripping it all over his clothes. Papyrus couldn’t hold it back, he broke down in fits of laughter. This only fueled sans excitement, and he proceeded to bathe in it. It was the greatest thing Papyrus had ever seen, and wished he had a camera so he could record it.   
But that soon stopped when he heard a gag. Looking down he saw sans, covered in spaghetti, with a terrified look on his face. “Sans?’ papyrus asked. Sans held up his hands, examining them. “P-papy-r-r-rus? Wha-what-t-t is happen-ning?” he said. Papyrus was frozen with fear. Adult sans’s voice had just come out of baby sans’s mouth, and he seemed to be aware of his surroundings. Then his face went pale, and sans fainted. Papyrus wasted no time, wrapping him in a blanket, spaghetti and all, and ran out the house. He needed to get to Hotland. He might just be able to get sans back if he’s fast enough.


	5. The Thought

**Notes for the Chapter:**

> Sorry I've been gone so long! Just graduated high school, woo hoo! School and graduation had taken up so much of my time, but now that it's over I can update my stories!! Yay. hope you enjoy

Sans was quiet, only sharp breaths being heard every now and then. Papyrus sat in a chair in the corner, waiting for alphys’s diagnoses. Her hands clicked over every tiny rib, checking for any breaks. “s-so far I see nothing wrong.” She stuttered. Papyrus sighed hard. “oh sans.” He whimpered. Alphys rewrapped sans in his blanket then approached Papyrus. “at least h-he’s healthy.” Alphys reassured handing back sans. Papyrus nodded. 

The walk home was slow. Papyrus cradled a sleeping sans close to his chest, his mind in deep thought. The thought of sans staying a child made his soul feel heavy. Sans had always been his number 1 fan, and knowing that his number 1 fan was now a number 1 priority was a lot to take in. Papyrus knew he was being selfish. Heck, sans had pretty much raised Papyrus. At least he could return the favor. 

A loud crunching of snow could be heard behind Papyrus. Turning, Papyrus was met with a high speed Undyne making her way towards him. Papyrus jumped to the side as Undyne dive bombed him. “don’t try and doge me Papyrus. I know you’ve been slacking!” she yelled. “undyne, please stop! I can explain!” papyrus yelled, dogging another attack. “no excuses! Training is training.” Undyne said. With a wide swing, Undyne knocked Papyrus back onto his back. 

Standing over him, her fanged smile glistened against the pure white snow. “u-undyne!” papyrus stuttered nervously. “I guess we can begin training not!” she said, raising her foot. A small whimper caught Undyne off guard, causing her to take a step back. Sitting up, Papyrus unwrapped the top portion of the blanket, revealing the small unhappy baby bones. The shaking had most likely woken him up, and now he was not very happy.  
Undyne took a few more steps back in shock, her arms going up defensively. “w-w-w-what is this?” she stuttered. Papyrus stood up, patting the snow off his battle body. “I’m sorry Undyne, I should have told you. You see, sans kind of got a little mixed up in one of Alphys’s experiments and this happened. But it’s not alphys’s fault!” papyrus explained. Undyne stayed quiet, her eyes glued to the blanket. “so, sans got turned into a baby.” She finally asked. 

“um, well, yeah I guess.” Papyrus said. “NGAHHH I CAN’T BELIEVE THIS!!” she yelled. Sans yelled out in fear at her sudden outburst, his soft face tainted with tears. “undyne please!” papyrus said angrily.   
Undyne took a step forward, reaching his hands out slowly. “c-can I hold him? I may not be the best with kids but.” Undyne whispered. With a sigh of exhaustion, papyrus slowly handed the baby bones to Undyne. She cradled him in her arms unsteadily. 

Sans seemed to calm down slightly, but when undyne smile, sans let out a scream, causing her to quickly hand him back to Papyrus. “I guess he’s just not very comfortable with you.” Papyrus laughed weakly. They both stood in silence. Then she said it.

“papyrus, what are you going to do if he stays like this?” she asked in a calm voice. 

Papyrus could feel his bones freeze up, his soul quivering. He hadn’t thought of that yet. What would he do if sans did stay like this? “hey, you alright?” undyne said, noting papyrus’s sudden change of attitude. Papyrus straightened up and nodded his head. “y-yeah, I’m fine. I’ve got to get sans home. He’s probably hungry.” Papyrus said. 

Then he turned and ran before Undyne said anything.


	6. The Decision

**Notes for the Chapter:**

> Sorry I haven't been updating much. but hopefully there will be more to come

When Grillby got done with work, he returned to the skeleton’s home. He had decided this was the best place sans could be, and the most convenient since Grillby lived in a group home and the neighbors weren’t very fond of the loud crying all the time. Stepping inside, Grillby sighed with relief. Work was done, now for his second job.

“Papyrus I’m, huh?” Grillby said. Sitting on the couch was Papyrus, feeding sans an empty bottle. He was visibly shaken, something Grillby thought he’d never see.

“Papyrus, what’s wrong?” Grillby asked as he made his way around the couch. Papyrus had tears running down his face. He looked at Grillby nervously. “w-we can’t change him back, can we?” papyrus cried. Changing him back, a topic Grillby tried not to speak of. His soul was doing flips in his chest now, unable to come up with an answer. Finally, he spoke. “I don’t know Papyrus; I just don’t know.” He said. Papyrus then began to sob loudly, making sans cry with him. Grillby hastily took sans from Papyrus’s arms, shushing him.

“Papyrus, this is no time to cry. Your brother is scared for you too.” Grillby said. Papyrus took in a shaky breath, wiping the tears from his face. “your r-right. This is n-no time for tears,” papyrus sniffed.

He reached out again, taking sans from Grillby’s arms. “I’m sorry sans, I didn’t mean to worry you.” Papyrus reassured sans. Sans whimpered quietly. Grabbing ahold the hoodlie Papyrus was wearing, he yelled, “Papyrus!” papyrus and Grillby were both taken back by this sudden yelled. It had been the first real word sans had said, and he even said it perfectly.

“you, said my name.” papyrus said flabbergasted. Then again, sans yelled another word. “Papyrus, no cry! No cry! Be smile!” he yelled. There was something different about sans. Not only was he speaking, but it seemed he was getting bigger. “oh my, he’s growing.” Grillby breathed. “he’s growing! It’s working, he’s going back to normal!” papyrus yelled ecstatically. Though he may not have grown much, it was giving Papyrus hope.

“I’m making my decision. I’m going to fix this.”


	7. Growing

It started with walking, to running, to saying a few words to whole sentences. Sans was growing fast. It was funny to Papyrus knowing how sans had watched him grown from a baby bones to the man he is today, but now the roles were reversed. Papyrus now had memories that he couldn't have of young sans. Grillby was enjoying it too. His love for babies was out of control Papyrus had noted. It was interesting watching the usually emotionless Elemental laugh and gawk at every thing sans did. It was cute. But with each milestone, Papyrus became more worried. If he keeps growing like this, would he grow past his original age? It worried Papyrus deeply. 

Papyrus sat at the kitchen table, his chin resting on his hands. He had been thinking about it again, the possibility sans never stops growing. He was at least age 6 now, the most verbal age. A soft tug came from the hem of Papyrus's shirt. He glanced down to see a wide eyed sans looking up at him. "Papy, what's wrong?" sans asked. He was so innocent at this age. "hehe, sorry I was just thinking."Papyrus said trying to brush it off. Sans didn't seem impressed. Although he was the most innocent at this age, he was also the most observant. "you're lying." sans pouted. "y-yeah, sorry. I've just had some things on my mind." Papyrus sighed. "Geez Papy, you think too much." sans laughed. Yup,he was defiantly cute. "why don't we go to Waterfall today? Give us something to do." Papyrus insisted. sans seemed to light up like a lightbulb. "Can we go to the dump? I want to explore!" sans said. Although Papyrus wasn't very comfortable with sans version of exploring (which meant climbing up piles of garbage), he agreed.

The walk wasn't very long but Papyrus enjoyed the amount of time he spent with sans. As he grew, Papyrus wasn't sans's interest anymore. His eyes were set on finding every hiding spot in the house and soon every spot in Snowden. They hadn't been to Waterfall yet, but with the little bit of memory from the past, sans was able to remember certain locations. When the reached the dump, sans let go of Papyrus's hand and ran to the nearest pile. It was like there were stars in his eyes as he gazed up the giant pile. "this one is huge!" he gasped. It wasn't that big to Papyrus, but for sans's size it must have been a mountain. "Be careful sans. Stay close to me." Papyrus warned. Sans ignored Papyrus's warnings and began to ascend the pile. "S-sans come back here!" Papyrus cried. Knowing sans didn't hear him, or wasn't listening, he began climbing the pile too. It was a lot harder than Papyrus thought. Slipping on smooth metal and loose crap, he almost ended back at the bottom a few times. Finally getting his footing, Papyrus reached the top. "S-sans, p-please don't do that again." Papyrus panted. sans sat opposite from him, his back turned. "sans?" Papyrus asked nervously. Silence sat between them as though it was physically possible.

"papyrus." sans said slowly. Papyrus was taken aback by the sudden voice. It was deep, like his original self. Wait, this happened before! "S-sans, is that you? I mean, the real you?" Papyrus stuttered. Sans turned slightly, his wide grin soft. "You mustard read my mind." he joked.


	8. Answers

Although his body was of a child's, sans's older persona was present. "Sans, your back! But how?" Papyrus asked. Sans scratched the back of his head. "guess my old self broke through. It will probably only last a few minutes but for now I should answer some questions." sans said. "Answers?" Papyrus asked confused. Sans nodded. "I bet you're wondering if i'll keep growing or stop at my original age. That and if I will remember my time as a baby bones." sans said. Papyrus nodded. "First off, yes I will stop at my original age. Don't worry, I won't turn into an old man." sans said. Papyrus sighed with relief. That was a weight off his shoulders. "second, I will only remember parts of my time as a baby. Babies don't have a good memory so as I grow, I will forget." he continued. Papyrus nodded.

But one thing was confusing Papyrus. "wait, how do you know all this." Papyrus asked. sans looked away nervously. "While I grow here, my adult consciousness is floating in a blank space i guess you could call it. That's where I met, um, you wouldn't understand." sans said. Papyrus reached forward and took sans's small hand. "No brother, don't do this too me. I've been through so much already! I need to know!" Papyrus pleaded. Sans sighed defeated. "well, if you say it that way. I can't say his name but, he's and old friend I guess. He explained everything to me. I can't tell anymore, I don't know the consequences." sans explained, pulling his hands away. He wanted more, but if it meant hurting sans, Papyrus could wait. "alright brother, I understand." Papyrus said. 

Sans looked up to the cave ceiling and sighed. "my time is almost up here. I'll just go back to being a kid again." he said sadly. "W-what! Already?" Papyrus yelled. As much as sans wanted to stay with his brother, his time was almost up and he would go back to the dark place in his consciousness. They sat quietly together, looking other ways. "Pap, I'm sorry for all the pain you've had to go through. If I wasn't so clumsy this wouldn't of happened." sans said quietly. Papyrus looked over at his brother. "Sans." he breathed. Sans stood up, placing hands on his hips with pride. "well, I guess I'll see you later. Treat kid me well." Sans said. The with all the little might her had, sans jumped forward and slid down the pile.

"SANS!" Papyrus yelled. Papyrus jumped after him in shock, sliding down the pile along with him. at the bottom papyrus skidded to a halt in shallow water. he glanced up to where sans was and was met with a set of confused eyes. "Papy, what are you doing?" young sans asked. Papyrus chuckled under his breath. "nothing." he laughed. Standing up and dusting himself off, Papyrus extended his hand out to sans. "Ready to go home? I'm thinking of making spaghetti." Papyrus said. With a small hand in his, the two made there way home.

"Papy, your spagetti isn't that good." sans grumbled. "THE GREAT PAPYRUS'S SPAGHETTI IS THE BEST YOU HAVE EVER TASTED!" Papyrus yelled.


	9. The man

**Summary for the Chapter:**

> GASTERGASTERGASTERGASTERGASTERGASTERGASTERGASTER!!!!!!!!!!!!!!!!!!!

**Notes for the Chapter:**

> Shit is about to go down

Sans was growing fast. He was around age 17 when Papyrus stopped worrying. Sans was healthy, no changes in his 1 HP. But what sans had told his the day they went to waterfall was worrying him. A man who they knew but Papyrus couldn't remember. Who was he, and was he dangerous? Sans had said he didn't know the consequences of their conversation, so was he in evident danger? Papyrus couldn't stop thinking about it. Finally, Papyrus had enough. If sans wasn't going to remember these past weeks anyways, what was the harm?

Sans sat on the couch staring at the TV. It was another one of Mettatons reruns that they must of seen at least fifty times. Sans had become distant between ages 13 and 17, most likely because it was the rebellious age. Papyrus took a seat next to him, trying not to bounce the seat too much. Sans glanced over to him then back at the tv. "What is it? I don't want to go out if that's what you were going to ask." Sans grumbled. Yup, he was rebellious. "well, that's not what I was going to ask. I was wondering if you knew of someone? I can't quite remember what his name was or what he looked like, but I just thought I would ask." Papyrus stuttered. "How can I remember someone if I don't know anything about them?" Sans spat. Papyrus felt defeated. This was harder than he had thought. "w-well, he's an old friend of ours." Papyrus said.

Something in sans must of struck a nerve because he tensed up, eye lights going out. He seemed to tremble for a moment before turning to Papyrus. Papyrus felt like he was looking into hell itself. The darkness of sans's eyes seemed to swallow him alive. "you shouldn't have said that." a dark voice said. Then suddenly sans's eye lights returned, wavering as tears filled his sockets. "P-Papyrus, why did you have to.....

Papyrus barely caughtsans as he fell off the couch. He lay limp in his arms, unconscious. "what have I don't?" Papyrus whimpered as tears formed in his sockets. He shook sans lightly, hoping it would wake him. "sans, hey, wake up this isn't funny. Come on wake up, hey, hey, sans." Papyrus said as he shook sans harder. He wasn't responding. 

"SANS, SANS WAKE UP PLEASE I'M SORRY PLEASE WAKE UP!" Papyrus screamed. This wasn't the same as when it first happened. Something was defiantly wrong. The front door was slammed open and a worried Grillby ran in. "Papyrus what's wrong?" he yelled as he ran in. "Grillby, help sans isn't waking up!" Papyrus sobbed. Grillby knelt down next to sans's lifeless body. He pulled up sans's stats only to gasp in shock. "his HP isn't dropping, but something is happening. His magic is overreacting to something!" Grillby explained. "What do you mean overreacting?" Papyrus asked. "look for yourself. His magic is increasing at an alarming rate. If it keeps growing with power, it might explode, killing us and him. We need to get him to Alphys quick." Grillby said. Grillby reached forward, taking sans from Papyrus's arms. 

The two then made their way to the lab at alarming speed.


	10. Clues

**Summary for the Chapter:**

> Alphys might know who the man is

Papyrus awoke with a start, then immediately groaned as pain shot up his spine. Looking around the memories from the night before began coming back. He was in Alphy’s lab. After san had blacked out and his magic level rose to dangerous levels, him and Grillby had rushed sans to the lab. Glancing over to his side, Papyrus’s eyes landed on sans’s sleeping form. Plugged up to numerous devices, sans seemed to be swallowed by the many blankets around him. For most monsters, when your power level goes up, your temperature goes down. This is because magic energy is very hot, and letting it out would then heat the body back up. But for sans’s case, the energy couldn’t be let out so he became very cold. Hard to believe knowing he’s just a pile of bones. It worried Papyrus. But the calm expression on san’s face made him feel better. “you really got chilled to the bone didn’t you?” Papyrus snickered. 

Footsteps approached papyrus, and he turned to meet their gaze. Alphys stood with two mugs in her claws, presumably hot chocolate. “I-I-I b-brought hot c-chocolate.” She stuttered. The two sat in silence as they sipped their drinks. Alphys looked over to papyrus whose gaze never left his brother. She began to feel nervous. She knew it was her fault and there was nothing she could do. She didn’t realize she was crying until Papyrus looked at her worriedly. “Alphys, what’s wrong?” Papyrus asked. Alphys dropped her mug to the ground as she reached up and grabbed her face.  
“I’m sorry a papyrus this is my fault, this is all my fault.” She sobbed.   
Papyrus reached forward, placing a hand on her shoulder. But this movement caused Alphys to retaliate into a fit of misery. “I’m sorry, so sorry, this all my fault. It’s because of me he’s like this. I’m a failure, failure. I should die I shouldn’t be alive, please please please end it end it….” “ALPHYS!” papyrus yelled suddenly. Alphys looked up shocked. Papyrus was standing now, his sockets blank. This was something Alphys had never seen before. Papyrus had always been so sweet and innocent, but now, this was a completely different Papyrus. “can’t you tell this isn’t time for your rambling. This isn’t your fault. Sans wanted to help so it was his fault for being so careless. And blaming yourself, no, accusing yourself of this isn’t helping the issue at hand!” papyrus said. By now his eye lights had returned and tears streamed down his face. Alphys swallowed hard. “I’m sorry Papyrus.” She whispered. The two sat in silence again, both soundlessly crying. After a few minutes of this, papyrus spoke up. “I need you to help me with something.” He said. 

Alphys looked at Papyrus confused. “w-what is it?” she asked. “before sans blacked out, I was speaking to him about something, well, someone. I don’t know who they are or what they look like but they must have a deep connection with sans for him to have this strange episode. He explained it as, an old friend.” Papyrus explained. And old friend. The words danced around Alphy’s mind excitedly. When they were younger, sans had mentioned an old friend while they looked around the lab after Alphys was named royal scientist. Then it hit her. “follow me, I think I know something.” She said pulling papyrus’s arm.


	11. The Void

The darkness had never felt more suffocating. As lights came back into his eyes, sans could feel a heaviness in his bones. The Void, a place he wish he’d forget. Straitening his spine, sans glanced around. He was floating in a sea of darkness. It was cold and smelled of metal and burnt magic. He knew why he was here. “Gaster, I know you’re here. Just come out and get this over with.” Sans yelled. Although it was dark, sans could make out a darker shape moving in the distance. It moved like what you would describe a squid would move. As it got closer, sans could make out the face. Pale with dark eyes, and deep cracks. Him. “Sans, what a surprise. I didn’t expect you to be here.” He teased. “very funny, but I know you were the one who called me here.” Sans grumbled.   
Gaster dashed forward, his distorted face engulfing san’s vison. “now, now sans. That isn’t how you speak to your superior.” He laughed. Sans pushed himself back, which was a challenge knowing he was floating in negative space. “yeah, yeah. My superior who still doesn’t understand personal space.” Sans said.

“Haha, I find that humorous.” Gaster laughed. Sans groaned at the joke. It wasn’t very funny coming from a half dead octopus skeleton guy. “alright, what do you want?” sans sighed. “Its about your brother. He’s getting to close to knowing the truth about me. You know I put that spell on everyone but you when I fell into the Core. But it seems dear Alphy’s may have uncovered things that might break it.” He explained. “and? What’s your point? Why don’t you want anyone to remember you? I mean, you are the old royal scientist. People should be remembering you as a hero.” Sans said. Gaster seemed taken back for a moment, then let out wheezing laugh. “that is true. But If I’m remembered, then I will be trapped in the void. With people not knowing I am alive, my consciousness is able to leave and explore the living world.” Gaster explained. “Geeze, just die already you old geezer. No one wants your creepy ghost body floating around.” Sans spat. 

The void began to feel cold, colder that it was before. Sans could feel his bones tremble. “sans, you don’t understand. I am the void, and you are in it. I can bring others here too. Like your brother. Your friends. And I can remove the spell and trap us all in here. Wouldn’t that be pleasant?” Gaster bellowed. Sans was petrified. The man he looked up to, the man who gave him a home, a job, and a sustainable life so he could take care of his brother, was now this monster in front of him. “Gaster, please let me out. I promise to stop papyrus and Alphys, destroy the evidence, and leave you alone.” Sans said. “heh, melting under the pressure? Maybe I should just keep you here. But, you are boring, and your jokes are poor. But your brother is very excitable. I want to see is innocent face crack under the pressure.” Gaster laughed. 

A crackle of magic leaped through the air. The void was reacting to another power source. Gaster’s smile stretched wide. “oh, so you finally show me your true colors.” Gaster chuckled as he stared down a large Gaster blaster. 

 

“I’m pretty chill with a lot of things, but, don’t ever Say ANYTHING ABOUT MY BROTHER!!”


	12. The Core

The room was small and dusty with only one desk lamp. Papyrus was starting to feel claustrophobic, but he maintained his composer as Alphys sifted through some papers. “this was the old royal scientist’s room, the one before me.” Alphys explained. Papyrus glanced at the far wall, noticing old photographs. There were pictures of different scientists and King Asgore and his family, but what stood out to Papyrus was an old photograph of two young skeletons. In closer inspection, Papyrus was shocked to find it was him and sans when they were younger. “Oh, my stars Alphys, is that me and sans?!” he gasped. Alphys agusted her glasses, then sighed. “I was hoping you wouldn’t see this.” She groaned. It was as though he was talking to another person. Alphys had never been a calm monster, and hearing her talk so monotone without stuttering, it was otherworldly. “Alphys, who was this guy anyways?” papyrus asked. Alphys took a deep breath, the handed papyrus a picture. “his name was W.D. Gaster, the first royal scientist.” She said. The picture was of a tall, slim skeleton monster with two toned eyes. He stood with a group of other scientist in a group picture. Papyrus didn’t recognize any of them except a short familiar monster. Standing in the front with a wide smile was sans. The date in the corner said it was June 4 20XX. Sans was about eighteen years old at that time, almost ten years ago. Papyrus had no memories of sans ever working at the labs, which was strange since Papyrus remembered everything. “you can’t remember, can you?” Alphys asked. Papyrus turned to Alphys confused. “just as I thought. Don’t worry, no one remembers. It was only a year ago, when sans happened to bring it up in a conversation.” Alphys sighed. “does sans remember?” Papyrus asked. Alphys looked to the floor, wringing her hands. “w-well, it seems so. He spoke about Gaster a lot after we opened the door to this office. Somehow we all lost our memories when he died.” She explained. “wait, he’s dead? How did her die?” papyrus yelled. With a shaky hand, Alphys pulled up a small curtain behind the desk, flooding the room with light. Papyrus could feel his body get cold as he stared at the scariest thing he had ever seen.  
The core


	13. Sans

**Notes for the Chapter:**

> sorry for the short chapter

The core was what gave the underground power. He had heard stories about it, but he had never seen it himself. “Gaster created the core, but tragically fell into it when he was working. His dust was never recovered.” Alphys said grimly. Papyrus stood shocked. “but, sans said that he spoke to him.” Papyrus breathed. Alphys turned to him suddenly. “w-what do you mean he spoke to him?” she asked. “w-well, sans said his adult consciousness floats in a free space, and that where he spoke to Gaster.” Papyrus explained. The color in Alphys face drained to white. “it can’t be. Then the rumors are true. Then that means,”  
A loud beeping was suddenly heard from down the hall causing papyrus and Alphys to jump. “the monitor, SANS!” Alphys yelled.


	14. The battle

The battle of the two monsters seemed to drag on forever. Sans was getting tired, but Gaster seemed to have copious amounts of energy. “I never thought an old geezer like you could have so much energy>” sans panted. “and I never though a young one like you would be so weak.” Gaster laughed. Blasters were fired, bones were thrown, but sans couldn’t land a hit on Gaster. It was starting to toll on sans, and he could feel his physical body begin to be affected. He wasn’t sure what had caused him and Gaster to become so violent in the first place. Sans noticed an opening and threw a bone, spearing Gaster in the side. But Gaster’s body seemed to melt around the bone, returning to normal as though it had never been touched. “now that not fair.” Sans grumbled. This only made Gaster laugh in admiration. “sans, just give up. I win.” Gaster laughed. “nope, not gonna.” Sans snickered. The battle lasted another twenty minutes when sans finally felt his body give out. Falling to his knees, sans glared at Gaster. “sans, this isn’t how I was hoping to end.” Gaster said. “not how I intended it to end either.” Sans panted. “so, what are you going to do, kill me?” sans asked. “excepting your fate? I never knew you would stoop to that level.” Gaster laughed. “oh, shut up, I know you won’t do anything to me. You aren’t that evil.” Sans laughed. A sharp pain was felt in sans left zygomatic bone as a sharp crack was heard. His ear-piercing scream seemed to be swallowed by the void’s walls. “don’t worry, it will heal.” Gaster laughed darkly. White dots specked in sans vision as he began to black out. The last thing he was the horrifying disfigured face of his once good friend, W.D. Gaster.

The monitor was going crazy, charts off the walls. Alphys was doing everything to keep sans stable as papyrus screamed into sans face. It had gotten to the point that Alphys was sure sans was going to fall, but when the monitors suddenly when silent. “Alphys, is he dead?” papyrus sobbed. “n-no, he isn’t. hi-his stats a-are b-back to normal.” She said flabbergasted. There was a cracking sound, and papyrus looked down to see a small hairline fracture in sans zygomatic bone. Then sans opened his eyes. “sans, sans can you hear me?” papyrus sobbed. Sans glanced to papyrus, tears spilling out of his eyes. He whispered something but papyrus didn’t catch it. “what?” papyrus asked. “I WANT TO GO HOME!” sans yelled. It was a request papyrus couldn’t turn down. Later that day, papyrus took sans in his arms and headed home. Sans had done it, he had beaten Gaster.


	15. 28th

**Notes for the Chapter:**

> its over dammit

Sans stared out his window as fresh snow fell outside. “sans, come downstairs.” Papyrus yelled. Pushing himself up, sans slid on his pink slippers and made his way downstairs. As the bottom of the stairs, sans could hear whispers coming from the kitchen. He knew what was going on, but pretended to be oblivious. “where are you guys?” he called. Whispered laughter could be heard from the dark kitchen, indicating that there was someone there. Taking slow strides, sans entered the kitchen. The lights were abruptly turned on and the many cheers of celebration were let out. “Happy 28th Birthday!” everyone yelled. On the table was a large cake that had his name on it. He had done it. The time had finally stopped and he was no longer a child. He was back to normal. Sans couldn’t help but get a little chocked up as papyrus lifted him onto his shoulders. “that’s everyone. This is great.” Sans laughed. “it better be! I took care of you all this time!” papyrus yelled. Grillby seemed to get a kick out of that because he broke into a fit of giggles. Undyne and Alphys hugged each other, mettaton posed, napstablook did what napstablook does, and papyrus ran around the room with sans held high on his shoulders. For the first time in forever, sans was happy to be alive. He had friends and family to look out for him, and deep down inside, he could feel Gaster smiling from the core. Life was great.

As the party wined down, sans took a minute to step outside. The cool air against his face made his injury sting, but he knew it was a part of him now. “are you alright brother?” papyrus asked as he stepped outside. “yeah, just airing out my bones.” Sans said. “was that supposed to be a joke?” papyrus grunted. “I don’t know, you tell me.” Sans snickered. It felt good to be back to normal. “hey pap, I wanted to thank you for doing all this for me. I’m really glad to have a brother like you.” Sans said. They stood together for a few minutes when papyrus finally spoke. “is he gone, Gaster?” he asked. “heh, I knew you would say that. No, he isn’t, but I don’t think he will bug us.” Sans sighed, rubbing a bony finger over the crack in his face. “you don’t have to thank me sans. You practically raised me from a baby bones till today. I guess this is just paying you back.” Papyrus said. “yeah, I guess.” Sans said. “alright, no more moping. Get in here and eat some cake! I backed too much!” papyrus yelled. “you cake is the best.” Sans said. “OF COURSE IT IS, I THE GREAT PAPYRUS MADE IT AFTER ALL!” papyrus yelled. The rest of the night sans spent with his brother and it was awesome.


	16. Again?!

**Notes for the Chapter:**

> dammit Alphys! didn't you learn the first time?!

Alphys tinkered with the machine she had made. She was hoping that it would work but knowing how it affected sans, she was wary. “if it weakened sans then if might weaken the barrier. Although it may be dangerous, it’s worth a try.” She mumbled. With the last screw tightened, Alphys began to fire up the laser. It was aimed at a flower hoping it would drain its energy and kill it. The laser began to fire up and she looked down the barrel towards the flower. The laser was about to take off when Undyne ran in. “hey babe check this out!” she yelled. “n-no, go out of the way! The laser!” Alphys yelled. But it was too late. The laser hit Alphys square in the chest, igniting in a bright light. As the smoke cleared, Alphys approached the remnants of undyne’s clothes. “oh no.” Alphys breathed. Buried under all the armor was a small, helpless, baby Undyne. Picking her up and examining her, a small smile came across Alphys face. “m-maybe this isn’t so bad.” She chuckled.


End file.
